Patent application number | Description | Published |
20090210583 | RESERVED DEVICE ACCESS CONTENTION REDUCTION - A computer program product, an apparatus, and a method for reducing reserved device access contention at a control unit in communication with a plurality of operating systems via one or more channels are provided. The computer program product includes a tangible storage medium readable by a processing circuit and storing instructions for execution by the processing circuit for performing a method that includes receiving a command message at the control unit from a first operating system, including an I/O operation command for a device. A device busy indicator is received, indicating that a second operating system has reserved the device. The command message is queued on a device busy queue in response to the device busy indicator. The control unit monitors for a device end indicator. The device busy queue is serviced to perform the I/O operation command in response to the device end indicator. | 08-20-2009 |
20120117196 | SYSTEMS, METHODS, AND COMPUTER PROGRAM PRODUCTS FOR TRANSFERRING RESERVES WHEN MOVING VIRTUAL MACHINES ACROSS SYSTEMS - According to one embodiment, a host system includes logic adapted for receiving device information from a source system, logic adapted for building a virtual device based at least in part on the received device information, logic adapted for transferring a reserve of a storage device to the host system and/or receiving results of transferring the reserve to the host system, logic adapted for determining if the reserve is held by the host system, logic adapted for recording the reserve if the reserve is held by the host system, and logic adapted for sending a notification that the reserve is not held by the host system if the reserve is not held by the host system. Other methods, systems, and computer program products are also described according to various embodiments. | 05-10-2012 |
20120141115 | APPARATUS AND METHOD FOR CLEARING A FAULT CONDITION OVER A FIBRE CHANNEL PATH - A method for clearing a fault condition at a target device is disclosed herein. In selected embodiments, such a method includes detecting a fault condition at a target device and receiving N instructions before the fault condition is cleared, where the N instructions are unexecutable due to the fault condition. N fault condition indicators are transmitted in response to the N instructions. Clearing of the fault condition is detected when the fault condition no longer exists. Acknowledgments corresponding to the fault condition indicators are received, where each acknowledgment indicates that one of the fault condition indicators has been received. A fault clear indicator is transmitted only after both all N fault condition indicators have been received and clearing of the fault condition has been detected. A corresponding system and computer program product are also disclosed herein. | 06-07-2012 |
20120159003 | SYSTEMS AND METHODS FOR AVOIDING HOST LEVEL BUSY AND RETRY LATENCIES - In one embodiment, a system includes logic adapted for receiving a command from a first system, logic adapted for determining which resources are required to process the command, logic adapted for checking for the required resources before receiving data associated with the command, logic adapted for receiving the data from the first system, logic adapted for checking for the required resources after receiving the data when the checking for the required resources before receiving data indicated that the required resources were not available before receiving the data, logic adapted for sending a status to the first system if the required resources are not available after receiving the data, and logic adapted for processing the command if the required resources are available either before receiving the data or after receiving the data. In more embodiments, a method and computer program product for processing a command are also presented. | 06-21-2012 |
20120246277 | METHODS FOR TRANSFERRING RESERVES WHEN MOVING VIRTUAL MACHINES ACROSS SYSTEMS - According to one embodiment, a method includes receiving device information from a source system; building a virtual device on a host system based at least in part on the received device information; at least one of: transferring a reserve of a device stored on a storage device to a target system; and receiving results of transferring the reserve to the target system; determining if the reserve is held by the target system; recording the reserve if the reserve is held by the target system; and sending a notification that the reserve is not held by the target system if the reserve is not held by the target system. Other methods are also described according to various embodiments. | 09-27-2012 |
20120254566 | PREVENTION OF OVERLAY OF PRODUCTION DATA BY POINT IN TIME COPY OPERATIONS IN A HOST BASED ASYNCHRONOUS MIRRORING ENVIRONMENT - A primary storage controller is configured to communicate with a secondary storage controller via a system data mover. In response to receiving a command to perform a point in time copy of a source volume of the primary storage controller to a target volume of the primary storage controller, a determination is made as to whether the target volume of the primary storage controller is a source for an asynchronous data replication operation, initiated by the system data mover, between the primary storage controller and the secondary storage controller. In response to determining that the target volume of the primary storage controller is the source for the asynchronous data replication operation, initiated by the system data mover, the point in time copy of the source volume of the primary storage controller to the target volume of the primary storage controller is performed. | 10-04-2012 |
20120290729 | ESTABLISHING COMMUNICATION PATH GROUP IDENTIFICATION FOR MULTIPLE STORAGE DEVICES - Embodiments of the disclosure relate to setting up a logical path group identification for multiple data storage devices. An aspect of the disclosure concerns a computer implemented method that comprises receiving a host command to establish a group of connection paths between the host and a plurality of storage devices, identifying the group of connection paths, adding each one of the storage devices to the group of connection paths, and reporting to the host those storage devices that could not be successfully added to the group of connection paths. The method maintains host access security to the storage devices by not grouping a device when it is a reset event state. | 11-15-2012 |
20130166867 | PREVENTION OF OVERLAY OF PRODUCTION DATA BY POINT IN TIME COPY OPERATIONS IN A HOST BASED ASYNCHRONOUS MIRRORING ENVIRONMENT - A primary storage controller is configured to communicate with a secondary storage controller via a system data mover. In response to receiving a command to perform a point in time copy of a source volume of the primary storage controller to a target volume of the primary storage controller, a determination is made as to whether the target volume of the primary storage controller is a source for an asynchronous data replication operation, initiated by the system data mover, between the primary storage controller and the secondary storage controller. In response to determining that the target volume of the primary storage controller is the source for the asynchronous data replication operation, initiated by the system data mover, the point in time copy of the source volume of the primary storage controller to the target volume of the primary storage controller is performed. | 06-27-2013 |
20130209086 | CLEARING A FAULT CONDITION OVER A FIBRE CHANNEL PATH - A method for clearing a fault condition at a target device is disclosed herein. In selected embodiments, such a method includes detecting a fault condition at a target device and receiving N instructions before the fault condition is cleared, where the N instructions are unexecutable due to the fault condition. N fault condition indicators are transmitted in response to the N instructions. Clearing of the fault condition is detected when the fault condition no longer exists. Acknowledgments corresponding to the fault condition indicators are received, where each acknowledgment indicates that one of the fault condition indicators has been received. A fault clear indicator is transmitted only after both all N fault condition indicators have been received and clearing of the fault condition has been detected. A corresponding system and computer program product are also disclosed herein. | 08-15-2013 |
20140101256 | METHOD TO PREVENT I/O STARVATION OF SLOWER HOSTS IN A MULTI-HOST ENVIRONMENT - A method, system and computer-usable medium are disclosed for managing storage control unit input/output (I/O) operations in a multi-host environment. A storage control unit sends a busy status message when it has exhausted its resources to process new I/O requests. Once the utilization of the storage control unit's resources has subsided to a predetermined upper utilization value, it sends a availability status message to a first predetermined number of host systems that are owed a availability statue message. After the first predetermined number of availability status messages are sent, the storage control unit then waits for a predetermined period of time before sending a second predetermined number of availability status messages. | 04-10-2014 |